This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

Please enable Javascript to watch this video

HUNTSVILLE, Ala. - Many people in different areas of Madison County said they didn't hear outdoor warning sirens activate on Tuesday night when multiple tornado warnings were issued here.

You didn't hear them because they didn't go off, even though they should when a tornado warning is issued. We received hundreds of questions on Facebook, Twitter, through email and phone calls, so we are Taking Action to get answers as to why this system failed at such a critical time.

The Huntsville Madison-County Emergency Management Administration, which operates the outdoor warning system, said it is still investigating what happened.

"Madison County EMA is aware of reported issues with the Outdoor Warning System," the EMA said in a news release. "We are currently analyzing data to determine the effectiveness of the system's performance last night. Any necessary corrective actions will be administered. We will provide updates as they become available."

Jeff Birdwell, director of the Huntsville Madison-County Emergency Management Administration, said personnel monitoring the storms from the Emergency Operations Center, didn't notice problem with the sirens and then emails and calls started coming in.

"We’re in our data collection mode," Birdwell told WHNT News 19 on Wednesday. "And we don’t really have any specifics right now. But what we hope to do is dig down deep into that data and look and see what the issues were."

The system was changed recently to warn residents in a given area or "polygon" where a potential tornado's path is mapped. The move was aimed at not sounding the outdoor alarms in areas that aren't facing a possible threat and focusing on areas that appeared in the storm's way.

"You know in some cases we may actually find out that a report that came in that the siren didn’t go off. Well, it wasn’t supposed to. Because in that particular instance the siren was not located in the polygon," Birdwell said, adding, "we’re probably going to find some cases where the siren was located in the polygon and didn’t go off."

Birdwell stressed the outdoor warning system is not a catch-all system. It's designed for residents who are outside. He said residents in a well-insulated house or rooms may not hear it.

"But we do realize the importance of this system working correctly, and we’re in the beginning phases, but we’re going to get down to the root cause of what the problem is, so hopefully we don’t have this again," he said.

Birdwell acknowledged he couldn't recall a similar incident where the sirens were supposed to go off, but didn't.

"I cannot recall one. We’ve had issues where we’ve had more sirens go off than should, which you kind of can say, well that’s bad, but at least they all went off," he said. "But I can’t recall an incident where we had sirens that actually failed to go off."

He said experts working on the system today reported things appeared to be in working order. Birdwell gave no time estimate on when they expect to figure our what happened Tuesday. He said it depends on if the problems are within the central system or at various siren sites.

"Our first job is, is the system currently up and working like it’s supposed to? And that’s the first thing that we delved into this morning," Birdwell said. "And we are there, at least every indication we have is that we’re back on-line."

"The key here is we’re up and running like we need to be now, and we’ll find the problem."

WHNT News 19 will continue to pursue answers on what happened to the warning sirens.